Mineral material, for example rock, is gained from the earth for processing by exploding or excavating. The mineral material can also be natural rock and gravel or construction waste such as concrete or bricks, or asphalt. Mobile crushers and stationary crushing applications are used in crushing. An excavator or wheeled loader loads the material to be crushed into the crusher's feed hopper from where the material to be crushed may fall in a jaw of a crusher or a feeder moves the rock material towards the crusher.
A mineral material processing plant comprises one or more crushers and possibly other apparatuses such as screens. The processing plant may be stationary or movable.
FIG. 1 shows a mineral material processing apparatus, a mobile crushing plant 200 that comprises as the main processing apparatus a jaw crusher 100 for crushing of mineral material. The crushing plant 200 has a feeder 103 for feeding the material to be processed to the jaw crusher 100 and a belt conveyor 106 for transporting the crushed material farther from the crushing plant.
The belt conveyor 106 shown in FIG. 1 comprises a belt 107 adapted to pass around at least one roller 108. The crushing plant 200 also comprises a motor 104 and a control unit 105. The motor 104 can be, for example, a diesel motor that provides energy for use of process units and hydraulic circuits.
The feeder 103, the crusher 100, the motor 104 and the conveyor 106 are attached to a body 101 of the crushing plant which body in this embodiment comprises additionally a track base 102 for moving the crushing plant 200. There is known also an entirely or partly wheel based processing plant or a processing plant movable on legs. A mineral material processing plant is also known that is movable/towable by a truck or another external power source.
Mineral material processing such as feeding, screening, crushing and transporting incurs heat in actuators of the processing plant. The actuators such as a motor, lubrication apparatus and hydraulics are heat sources that are cooled by a cooler. FIG. 2 shows a known combination cell 10 that is arranged in the cooler of the processing plant. The combination cell 10 is layer-like such that there are arranged on top of each other in the same structure a charge air cooling cell 11 for cooling 1 of charge air, a fuel cooling cell 12 for cooling 2 fuel, a motor cooling liquid cooling cell 13 for cooling 3 the motor and a hydraulics cooling cell 14 for cooling 4 hydraulic oil of the hydraulics.
It is attempted to economically utilize the capacity of the processing plant to the full extent so that the crusher is continuously loaded with a great crushing power. The running time of processing plants is limited by administrative orders because of noise emissions particularly in urban environment.
A substantial noise emission is caused by a blower that is arranged in connection with the combination cell 10 by which blower the cooling is enhanced by blowing air through the combination cell. Half of the noise emission of the motor is estimated to be blower noise. High rotation speed required from the blower is difficult in a hydraulically driven cooling solution which rotation speed is determined by the greatest cooling demand. The determining factor is typically the cooling demand of the charge air, although its percentage of the combination cell 10 is relatively small (20 to 25%). Thus, the large sized blower of the cooler can rotate with full speed although there would be no need for cooling the hydraulics and the motor.
In the mineral material processing, air flow moves fine particles formed by the processing, and it is attempted to restrict the generating dust emission by dust binding. Dust prevention of processing plants such as crushing plants is often based on water spraying. Water is sprayed to a dust making point of the process such as a crushing chamber of the crusher for example with high pressure 200 to 300 l/h or without high pressure about the threefold relative to the previous. In cold circumstances water-based dust binding causes additional costs and requires use of heating solutions and possible additive agents. It is known to use as a heater an electrical resistor or return oil or leak flow of the hydraulics. If the water is placed in a water tank in a movable processing plant, it is a typical solution is to use the electrical resistor for frost-prevention of the water. Supply of electricity is, however, not self-evident and generating the electricity is not always possible in the movable processing plant.
An object of the invention is to provide a processing method and plant by which drawbacks present in connection with prior art can be eliminated or at least reduced. A particular object of the invention is to enhance the cooling of the processing plant. A particular object of the invention is to enable as long as possible processing time.